A Novel Structure for Double Negative NIMs towards UV Spectrum with High FOM

A novel ring structure is proposed for double negative NIMs at visible light spectrum with high FOM (e.g. about 11 at a wavelength of 583 nm) and low loss. Besides the effective medium theory, an equivalent circuit model is also given to explain physically why our novel structure can give double negative behavior with low loss. Adapted from the original ring structure, two other types of structures, namely, disk and nanowire structures, are also given to further push double negative NIMs toward ultraviolet (UV) spectrum

Initiatives in the Romanian eHealth Landscape

Even if the foundation in the field of eHealth was set almost half century ago, the current achievements’ status does not place Romania on a good position in a European ranking. The efforts made during the last years are promising, but they still cannot surpass the enormous gaps in many eHealth indicators. This is not a surprising fact because the eHealth level must be sustained by a healthy and stable sanitary system and infrastructure, which, in our country, is almost in collapse, especially now in the context of global economic and financial crisis. We consider being guilty for these circumstances the lack of a clear and solid mid-term strategy developed at the level of the Ministry of Health (MoH), harmonized in a global legal and regulatory framework as well, and also the non-correlated researcher groups interests. The good attitude of practitioners regarding the challenges of new technologies and the political will can still give a chance to the Romanian healthcare system and to its modern faces

Size Dependence and Convergence of the Retrieval Parameters of Metamaterials

We study the dependence of the retrieval parameters, such as the electric permittivity, the magnetic permeability and the index of refraction, $n$, on the size of the unit cell of a periodic metamaterial. The convergence of the retrieved parameters on the number of the unit cells is also examined. We have concentrated our studies on the so-called fishnet structure, which is the most promising design to obtain negative $n$ at optical wavelengths. We find that as the size of the unit cell decreases, the magnitude of the retrieved effective parameters increases. The convergence of the effective parameters of the fishnet as the number of the unit cells increases is demonstrated but found to be slower than for regular split ring resonators and wires structures. This is due to a much stronger coupling between the different unit cells in the fishnet structure.Comment: Journal-ref and DOI adde

Multi-gap individual and coupled split-ring resonator structures

Cataloged from PDF version of article.We present a systematic numerical study, validated by accompanied experimental data, of individual and coupled split ring resonators (SRRs) of a single rectangular ring with one, two and four gaps. We discuss the behavior of the magnetic resonance frequency, the magnetic field and the currents in the SRRs, as one goes from a single SRR to strongly interacting SRR pairs in the SRR plane. We show that coupling of the SRRs along the E direction results to shift of the magnetic resonance frequency to lower or higher values, depending on the capacitive or inductive nature of the coupling. Strong SRR coupling along propagation direction usually results to splitting of the single SRR resonance into two distinct resonances, associated with peculiar field and current distributions. (C) 2008 Optical Society of Americ

Planar designs for electromagnetically induced transparency in metamaterials

We present a planar design of a metamaterial exhibiting electromagnetically induced transparency that is amenable to experimental verification in the microwave frequency band. The design is based on the coupling of a split-ring resonator with a cut-wire in the same plane. We investigate the sensitivity of the parameters of the transmission window on the coupling strength and on the circuit elements of the individual resonators, and we interpret the results in terms of two linearly coupled Lorentzian resonators. Our metamaterial designs combine low losses with the extremely small group velocity associated with the resonant response in the transmission window, rendering them suitable for slow light applications at room temperature.Comment: 11 pages, 8 figure